Hi mayankv83,

Refer below link.

Download file from URL using C# and VB.Net in ASP.Net

Once you get the byte array you can save as file using below article.

Convert (Save) Byte Array as File using C# and VB.Net

Dear Dharmendra,

firebase url is right, if i run below code in VS2012 its download perfectly but when i try with VS2010 its return Bad request. Anyway its resolve issue. Thanks for your help.

var webClient = new System.Net.WebClient();
const string FIREBASEURL = "https://firebasestorage.googleapis.com/o/chats%2Fbytefury.png%7D?alt=media&token=b4687696-6dbe-4892-a298-0b7cddd19110";
var bytes = webClient.DownloadData(FIREBASEURL);
using (var ms = new MemoryStream(bytes, 0, bytes.Length))
{
  ms.Write(bytes, 0, bytes.Length);
  var image = System.Drawing.Image.FromStream(ms, true);
  image.Save(Server.MapPath("~" + "/MyImage5.jpg"));
  ms.Dispose();
 }